BACKHOUSE, WILLIAM (1593–1662), Rosicrucian philosopher, a younger son Samuel Backhouse, Esq., of Swallowfield, Berkshire, was born in that county 17 Jan. 1593, and entered Christ Church, Oxford, a commoner, in 1610, but left the university without taking a degree. At length, settling on his patrimony, he devoted his time to the study of the occult sciences, became a renowned alchemist, Rosicrucian, and astrologer, and gave great encouragement to the who were addicted to similar pursuits, especially Elias Ashmole, whom he adopted his son, and to whom he freely imparted the arcana of his mysterious lore. The subjoined laconic entries in Ashmole's diary show the intimacy of the friendship subsisting between them:— 26 April 1651: 'Mr. William Backhouse, of Swallowfield, in com. Berks, caused me to call him father thenceforward.' 10 June 1651: 'Mr. Backhouse told me I must now needs be his son, because he had communicated so many secrets to me.' 10 March 1652: 'This morning my father Backhouse opened himself very freely, touching the great secret.' And finally, under date 13 May 1653, Ashmole writes: 'My father Backhouse lying sick in Fleet Street, over against St. Dunstan's church, and not knowing whether he should live or die, about eleven of the clock told me, in syllables, the true matter of the Philosopher's Stone, which he bequeathed to me as a legacy.' It is almost superfluous to add that no hint is given as to the nature of this wonderful secret. Backhouse died at Swallowfield 30 May 1662. He married Ann, daughter of Bryan Richards of Hartley Westfield, Hampshire, by whom he had two sons (who predeceased him), and a daughter. Flower, who married, first, William Bishop, of South Warnborough, Hampshire, and secondly, her father's kinsman, Sir William Backhouse, Bart., who died 22 Aug. 1669.

Backhouse left in manuscript:

'The pleasant Founteine of Knowledge: first written in French anno 1413, by John de la Founteine of Valencia in Henault;' translated into English verse in 1644. MS. Ashmol. 58.

A translation of 'Planctus Naturæ: The Complaint of Nature against the Erroneous Alchymist, by John de Mehung.' MS. Ashmol. 58, art. 2.

'The Golden Fleece, or the Flower of Treasures; in which is succinctly and methodically handled the stone of the philosophers, his excellent effectes and admirable vertues; and, the better to attaine to the originall and true meanes of perfection, inriched with Figures representing the proper colours to lyfe as they successively appere in the pratise of this blessed worke. By that great philosopher, Solomon Trismosin, Master to Paracelsus; 'a translation from the French. M S. Ashmol. 1395. Wood adds that 'he was also the inventor of the "Way wiser" in the time of George Villiers, the first duke of Bucks.'